LittleMook - my DS is not at school yet but I am a school governor (fairly new). I've not looked at all the school's policies yet but I believe there is a sexism one.
What I think the new Equality Act means for schools (or though I'm not sure what is different re the previous legislation) is as follows:
"At the very least, schools must have
either, a three-year
a) race equality policy and action plan,
accessibility plan, disability equality
scheme and action plan, gender equality scheme and action plan, equal opportunities policy that covers sexual orientation, age and religion or belief, and a strategy for promoting community cohesion (in the form of a policy, plan, or working group for
example) Or
b) a three-year Single Equality Scheme and Action Plan that incorporates all the above policies, schemes and plans"
"Schools have statutory duties to promote race, disability and gender equality, and a duty to promote community cohesion. Schools must also not discriminate on the grounds of
sexual orientation, age or religion and
belief. The duties cover staff, learners
and people using the services of the school such as parents."
I would encourage you to write to the Chairman of the Governors requesting that a sexism policy is created.
It would be interesting if other feminist MNers with DCs at school requested their policies - to see if they exist, to see if they seem robust and then so that as parents you can check that the policy is being adhered to.